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8201556: Disallow reading oops in ClassLoaderData if unloading

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Move class_loader oop to an OopHandle, and assert that holder is alive when getting class_loader.

Reviewed-by: kbarrett, adinn
This commit is contained in:
Coleen Phillimore 2018-04-18 18:43:04 -04:00
parent 702ac597ad
commit ddfd4c33c6
22 changed files with 121 additions and 47 deletions
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27
src/hotspot/share/classfile/classLoaderData.hpp
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@ -28,7 +28,6 @@
#include "memory/allocation.hpp"
#include "memory/memRegion.hpp"
#include "memory/metaspace.hpp"
#include "memory/metaspaceCounters.hpp"
#include "oops/oopHandle.hpp"
#include "oops/weakHandle.hpp"
#include "runtime/mutex.hpp"
@ -84,6 +83,7 @@ class ClassLoaderDataGraph : public AllStatic {
static volatile size_t _num_instance_classes;
static volatile size_t _num_array_classes;
static ClassLoaderData* add_to_graph(Handle class_loader, bool anonymous);
static ClassLoaderData* add(Handle class_loader, bool anonymous);
static void post_class_unload_events();
public:
@ -220,8 +220,8 @@ class ClassLoaderData : public CHeapObj<mtClass> {
static ClassLoaderData * _the_null_class_loader_data;
ClassLoaderWeakHandle _holder; // The oop that determines lifetime of this class loader
oop _class_loader; // The instance of java/lang/ClassLoader associated with
WeakHandle<vm_class_loader_data> _holder; // The oop that determines lifetime of this class loader
OopHandle _class_loader; // The instance of java/lang/ClassLoader associated with
// this ClassLoaderData
ClassLoaderMetaspace * volatile _metaspace; // Meta-space where meta-data defined by the
@ -234,7 +234,7 @@ class ClassLoaderData : public CHeapObj<mtClass> {
bool _modified_oops; // Card Table Equivalent (YC/CMS support)
bool _accumulated_modified_oops; // Mod Union Equivalent (CMS support)
s2 _keep_alive; // if this CLD is kept alive without a keep_alive_object().
s2 _keep_alive; // if this CLD is kept alive.
// Used for anonymous classes and the boot class
// loader. _keep_alive does not need to be volatile or
// atomic since there is one unique CLD per anonymous class.
@ -265,6 +265,9 @@ class ClassLoaderData : public CHeapObj<mtClass> {
// Support for walking class loader data objects
ClassLoaderData* _next; /// Next loader_datas created
// JFR support
Klass* _class_loader_klass;
Symbol* _class_loader_name;
TRACE_DEFINE_TRACE_ID_FIELD;
void set_next(ClassLoaderData* next) { _next = next; }
@ -305,6 +308,8 @@ class ClassLoaderData : public CHeapObj<mtClass> {
MetaWord* allocate(size_t size);
Dictionary* create_dictionary();
void initialize_name_and_klass(Handle class_loader);
public:
// GC interface.
void clear_claimed() { _claimed = 0; }
@ -340,9 +345,7 @@ class ClassLoaderData : public CHeapObj<mtClass> {
// Returns true if this class loader data is for the boot class loader.
// (Note that the class loader data may be anonymous.)
bool is_boot_class_loader_data() const {
return class_loader() == NULL;
}
inline bool is_boot_class_loader_data() const;
bool is_builtin_class_loader_data() const;
bool is_permanent_class_loader_data() const;
@ -351,10 +354,7 @@ class ClassLoaderData : public CHeapObj<mtClass> {
// method will allocate a Metaspace if needed.
ClassLoaderMetaspace* metaspace_non_null();
oop class_loader() const { return _class_loader; }
// The object the GC is using to keep this ClassLoaderData alive.
oop keep_alive_object() const;
inline oop class_loader() const;
// Returns true if this class loader data is for a loader going away.
bool is_unloading() const {
@ -363,7 +363,7 @@ class ClassLoaderData : public CHeapObj<mtClass> {
}
// Used to refcount an anonymous class's CLD in order to
// indicate their aliveness without a keep_alive_object().
// indicate their aliveness.
void inc_keep_alive();
void dec_keep_alive();
@ -407,6 +407,9 @@ class ClassLoaderData : public CHeapObj<mtClass> {
static ClassLoaderData* class_loader_data_or_null(oop loader);
static ClassLoaderData* anonymous_class_loader_data(Handle loader);
Klass* class_loader_klass() const { return _class_loader_klass; }
Symbol* class_loader_name() const { return _class_loader_name; }
TRACE_DEFINE_TRACE_ID_METHODS;
};